Add label background color and border

[drewtoto]

Currently, a label with font styles can be added and relatively positioned to a map feature. Switching layers between mostly dark maps and mostly light maps can make labels unreadable. For example, black text label on a normal Google map layer is easy to read, however, the same black text label on Google a Google satellite map layer is very difficult to read.

This feature includes support for label background color, label border (size and color), and label padding (which is not supported by VML renderer).

Attached is an implementation of stated feature for SVG and VML renderers. Also included is an example.

[drewtoto]

Sorry, this ticket is a duplicate and result of a double submission. Refer to #2349.